Resonator coil having an asymmetrical profile

ABSTRACT

Embodiments herein are directed to a resonator for an ion implanter. In some embodiments, a resonator may include a housing, and a first coil and a second coil partially disposed within the housing. Each of the first and second coils may include a first end including an opening for receiving an ion beam, and a central section extending helically about a central axis, wherein the central axis is parallel to a beamline of the ion beam, and wherein an inner side of the central section has a flattened surface.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation application of U.S. Non-Provisionalapplication Ser. No. 16/734,746, filed Jan. 6, 2020, entitled “RESONATORCOIL HAVING AN ASYMMETRICAL PROFILE,” the entire contents of whichapplications incorporated by reference herein.

FIELD OF THE DISCLOSURE

The present disclosure relates generally to high-energy ion implantersand, more particularly, to a helical resonator coil having anasymmetrical profile.

BACKGROUND OF THE DISCLOSURE

Fabrication of power electronics devices used, for example, forautomotive applications, high resolution light sensors, and othercomplex 3D semiconductor structures, requires deep doping ofsemiconductor materials. This requirement translates into very highenergies of the species to be implanted. For instance, to dope at 5 μmdepth into silicon, the energy for B, P, and As may be 4.2 MeV, 10.5MeV, and 14 MeV, respectively. Even using multiply charged ion species,these energies are not achievable in regular dc voltage acceleratorsbecause of vacuum breakdown limitation.

One method to obtain such high ion energies is radio frequency (RF)acceleration. For example, a linear accelerator uses a series of RFresonant cavities, which boost the ion energy from tens of keV to a fewMeV. In a resonant RF cavity, the RF energy is transferred from the RFgenerator to an RLC circuit composed of a coil and a cavity. As thequality factor (Q) of the cavity goes higher, so does the availableacceleration voltage. However, the quality factor is limited by theresistance of the system, mainly given by the resistance of the coil.

In some cases, the resistance of the RF resonant cavity can be decreasedby increasing the size of a chamber defining the RF cavity. However,increasing the chamber size will also increase the cavity capacity andalter the resonant frequency. Furthermore, decreasing resistance of ajunction to ground and a gap resistance are typically difficult tomodify.

What is therefore needed is a solution to decrease system resistance andincrease the quality factor.

SUMMARY OF THE DISCLOSURE

In one approach, a resonator may include a housing, and at least onecoil disposed within the housing. The at least one coil may include afirst end coupled to an electrode, the electrode operable to accelerateions, and a central section connected to the first end, the centralsection extending helically about a central axis. An inner side of thecentral section may have a flattened surface, and an outer side of thecentral section may have a curved profile. The at least one coil mayfurther include a second end connected to the central section, thesecond end coupled to the housing.

In another approach, a resonator of an ion implanter may include ahousing defining an internal cavity, and a first coil partially disposedwithin the internal cavity. The first coil may include a first endcoupled to a first electrode, the first electrode including a firstopening for receiving an ion beam, and a first central section connectedwith the first end, wherein the first central section includes a firstplurality of loops extending helically about a central axis, and whereineach of the first plurality of loops has a first flattened surface. Theresonator may further include a second coil adjacent the first coil, thesecond coil including a second end coupled to a second electrode, thesecond electrode including a second opening for receiving the ion beamfrom the first electrode. The second coil may further include a secondcentral section connected with the second end, wherein the secondcentral section includes a second plurality of loops extending helicallyabout the central axis, and wherein each of the second plurality ofloops has a second flattened surface.

In yet another approach, a resonator of an ion implanter may include ahousing defining an internal cavity, and a first hollow coil partiallydisposed within the internal cavity. The first hollow coil may include afirst end extending outside the housing and coupled to a firstelectrode, the first electrode including a first opening for receivingan ion beam. The first coil may further include a first central sectionconnected with the first end, wherein the first central section includesa first plurality of loops extending helically about a central axis, andwherein each of the first plurality of loops has a first flattenedsurface. The resonator may further include a second hollow coil adjacentthe first coil within the internal cavity, the second hollow coilincluding a second end extending outside the housing and coupled to asecond electrode, the second electrode including a second opening forreceiving the ion beam from the first electrode. The second coil mayfurther include a second central section connected with the second end,wherein the second central section includes a second plurality of loopsextending helically about the central axis, and wherein each of thesecond plurality of loops has a second flattened surface.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A depicts a perspective view of a resonator in accordance withembodiments of the present disclosure.

FIG. 1B depicts a perspective view of a resonator in accordance withembodiments of the present disclosure.

FIG. 2A depicts a perspective view of a coil assembly of the resonatorof FIG. 1B in accordance with embodiments of the present disclosure.

FIG. 2B depicts a perspective view of an electrode assembly of theresonator of FIG. 1B in accordance with embodiments of the presentdisclosure.

FIG. 3 depicts a circuit diagram of the resonator of FIG. 1B inaccordance with embodiments of the present disclosure.

FIG. 4 depicts a lumped element circuit in accordance with embodimentsof the present disclosure.

FIG. 5 depicts an end, cross-sectional view of a coil of the resonatorof FIG. 1B in accordance with embodiments of the present disclosure.

FIG. 6 depicts a side, cross-sectional view of a coil assembly of theresonator of FIG. 1B in accordance with embodiments of the presentdisclosure.

FIG. 7 depicts an end, cross-sectional view of a coil in accordance withembodiments of the present disclosure.

The drawings are not necessarily to scale. The drawings are merelyrepresentations, not intended to portray specific parameters of thedisclosure. The drawings are intended to depict exemplary embodiments ofthe disclosure, and therefore are not be considered as limiting inscope. In the drawings, like numbering represents like elements.

Furthermore, certain elements in some of the figures may be omitted, orillustrated not-to-scale, for illustrative clarity. The cross-sectionalviews may be in the form of “slices”, or “near-sighted” cross-sectionalviews, omitting certain background lines otherwise visible in a “true”cross-sectional view, for illustrative clarity. Furthermore, forclarity, some reference numbers may be omitted in certain drawings.

DETAILED DESCRIPTION

Ion implanters and resonators in accordance with the present disclosurewill now be described more fully hereinafter with reference to theaccompanying drawings, where embodiments of the methods are shown. Theion implanters and resonators may be embodied in many different formsand are not to be construed as being limited to the embodiments setforth herein. Instead, these embodiments are provided so this disclosurewill be thorough and complete, and will fully convey the scope of thesystem and method to those skilled in the art.

Embodiments herein describe a compact, asymmetrical coil design usefulfor a linear accelerator resonator capable of resonating at apredetermined frequency. The resonator may include first and secondcoils disposed adjacent one another and helically disposed about a samecentral axis. Each of the first and second coils may be hollow, with aflattened surface along an interior side thereof. The coil design of thepresent embodiments decreases coil resistance and, consequently,increases the quality factor of a resonant cavity.

Turning now to FIG. 1A, a resonator 10 of an ion implanter according toembodiments of the present disclosure will be described. As shown, theresonator 10 may include a housing 12 defining an internal cavity 14.The housing 12 may be an electrically grounded conductive housing (e.g.,aluminum) surrounding a radio frequency (RF) resonant internal cavity.Within the housing 12 is a coil assembly 25 including a coil 15. Thefirst end 18 may be coupled to an electrode 13 having a slit or opening16 formed therethrough. During use, an ion beam 17 may pass through theopening 16. A length, e.g., along the x-direction of the electrode 13,may be selected so that the ion beam 17 is accelerated across a firstgap when entering the electrode 13, and then accelerated again when itleaves the electrode 13. During the time that the ion beam 17 istraversing a central portion of the opening 16, the RF voltage changesfrom negative to positive. Such an arrangement is sometimes referred toas a double gap accelerator.

As further shown, the first end 18 of the coil 15 may be connected to acentral section 21, wherein the central section 21 includes a firstplurality of segments or loops 23 extending helically about a centralaxis 30. In this embodiment, the central axis 30 may generally extendperpendicular to the direction of travel of the ion beam 17. A secondend 32 of the coil 15 may be connected to the housing 12, which is atground potential. As will be described in greater detail below, the coil15 be made of hollow tubing with an approximately circular cross sectionincluding an inner side of the central section 21 having a flattenedsurface (not shown).

Turning now to FIG. 1B, a resonator 100 of an ion implanter according toembodiments of the present disclosure will be described. As shown, theresonator 100 may include a housing 102 defining an internal cavity 104.Within the housing 102 is a coil assembly 115 including a first coil 105and a second coil 106. The first end 108 may be coupled to a firstelectrode 112, while the second end 110 may be coupled to a secondelectrode 114. The first electrode 112 may include a first slit oropening 116, and the second electrode 114 may include a second slit oropening 118. During use, an ion beam 117 may pass through the first andsecond openings 116, 118.

As further shown, the first end 108 of the first coil 105 may beconnected to a first central section 121, wherein the first centralsection 121 includes a first plurality of segments or loops 123extending helically about a central axis 120. In this embodiment, thecentral axis 120 may generally extend parallel to the direction oftravel of the ion beam 117. The second end 110 of the second coil 106may be connected to a second central section 125, wherein the secondcentral section 125 includes a second plurality of segments or loops 127extending helically about the central axis 120. As shown, the firstplurality of loops 123 may generally be arranged end-to-end with thesecond plurality of loops 127.

The first and second coils 105, 106 may be symmetrically arranged withrespect to the walls of the housing 102 and with respect to one another.As shown, the first and second coils 105, 106 are helices wound in asame direction and sharing the central axis 120. Respective second ends133, 135 of the first and second coils 105, 106 may be connected by aplate 122 coupled to the housing 102, which may be grounded. In otherembodiments, the first and second ends 133, 135 may be directly coupledto the housing 102.

As will be described in further detail herein, the first and secondcoils 105, 106 may further share a same/single magnetic field passinglinearly along the central axis 120. In this arrangement, the ion beam117 can be accelerated three times, i.e., first when the ion beam 117enters the first electrode 112, then as the ion beam 117 is transmittedfrom the first electrode 112 to the second electrode 114 and, finally,when the ion beam 117 exits the second electrode 114. This is enabled bythe RF voltage changing from negative on the first electrode 112 andpositive on the second electrode 114 during the first gap acceleration,and then reversing polarity when the ion beam 117 goes between the firstand second electrodes 112, 114. The ion beam 117 may then reversepolarity once more when exiting the second electrode 114. Such anarrangement is sometimes referred to as a triple gap accelerator.

In some embodiments, the first and second coils 105, 106 are coppertubes with an internal channel to permit a cooling fluid to flowtherethrough. For example, internally flowing water within the first andsecond coils 105, 106 may help dissipate heat generated by electricalcurrent traveling along the conductive material of the first and secondcoils 105, 106. As will be described in greater detail below, each ofthe first and second plurality of loops 123, 127 has a flattened insidesurface facing the central axis 120.

The working principle of the resonator 100 is depicted in FIG. 2A. Inthis embodiment, RF energy may be transferred from an energy source(e.g., RF generator) through an exciter coil (not shown) and into thecoil assembly 115. The energy is stored in the coil assembly 115 asmagnetic energy given by the following:

$\begin{matrix}{W_{mag} = \frac{B^{2}}{2\mu_{0}}} & (1)\end{matrix}$where B represents a magnetic flux 140 and μ₀ represents magneticpermeability of the vacuum within the internal cavity 104.

Because the internal cavity 104 forms an RLC circuit, it will oscillatewith a certain frequency f₀, which at resonance, is given by thefollowing:

$\begin{matrix}{f_{0} = \frac{1}{2\pi\sqrt{LC}}} & (2)\end{matrix}$where L is the inductance of the coil assembly 115, and C thecapacitance of the resonator 100. Under resonance conditions, the energywill transform periodically from magnetic energy, which manifests asmagnetic flux 140 in the coil assembly 115, into electrostatic energy.

FIG. 2B demonstrates an electrode assembly 138 operable with the coilassembly 115 according to embodiments of the present disclosure. In thisembodiment, the electrostatic energy of the electrode assembly 138 maymanifest as electrostatic potential difference, demonstrated as contourlines 144, between the energized openings of the first electrode 112 andthe second electrode 114. In some embodiments, the electrostaticpotential difference W_(elec) is given by the following equation:

$\begin{matrix}{W_{elec} = \frac{ɛ_{0}E^{2}}{2}} & (3)\end{matrix}$where E represents electric field strength and ε₀ represents dielectricpermittivity of the vacuum within the internal cavity 104.

More specifically, supposing the ions travel from left to right in FIG.2B, and amplitude of the oscillating electrostatic potential is V_(max),the three-gap acceleration of the coil assembly 115 works as follows.When ions at an exit of a first grounded electrode 156 have anappropriate phase, the ions will see a potential drop [0−(−V_(max))] andwill be accelerated across a first gap 154 and toward the firstelectrode 112, which is energized. A maximum energy that the ions cangain is equal to the charge the ions transport (q) multiplied by thevoltage V_(max). If a distance of the first gap 154 and a second gap155, which is disposed between the first electrode 112 and the secondelectrode 114, are calculated together with the electrode lengths at theexit from the first electrode 112, the ions will see a 2V_(max)potential drop [V_(max)−(−V_(max))=2 V_(max)]. Therefore the energy theions will gain crossing the second gap 155 will be double the energygained crossing the first gap 154. Finally, for a third gap 158, whichis between the second electrode 114 and a second grounded electrode 160,the potential drop seen by the ions will be V_(max), and the ions willgain an additional qV_(max) energy, thus resulting in a 4qV_(max) totalenergy at an entrance in the second grounded electrode 160.

For an ideal case (i.e., no losses) the magnetic energy will convertentirely into electrostatic energy resulting in 1:1 energy conversionfrom the coil assembly 115 (magnetic energy) to the accelerating ion(kinetic energy). However, in real systems there are losses which limitthis energy conversion. In this case, the energy transfer may bequantified by the quality factor Q of the resonator 100, which is givenby the following equation:

$\begin{matrix}{Q = {2\pi\; f_{0}\frac{{Energy}\mspace{14mu}{stored}}{{Power}\mspace{14mu}{dissipated}}}} & (4)\end{matrix}$

The total energy stored in the resonator 100 will be equal to the totalenergy stored in the coil assembly, which is given by the followingequation:

$\begin{matrix}{W_{mag}^{\max} = {L_{coil}I^{2}}} & (5)\end{matrix}$wherein I represents the rms value of the electrical current flowingthrough the coil assembly 115. On other hand, the power dissipated inthe resonator 100 is given by the following equation:

$\begin{matrix}{P_{diss} = {R_{echiv}I^{2}}} & (6)\end{matrix}$wherein R_(echiv) represents the equivalent resistance of the resonatorcircuit. Under resonance conditions, this leads to

$\begin{matrix}{Q = {\frac{\omega_{0}L_{coil}}{R_{equiv}} = \frac{X_{Lcoil}}{R_{equiv}}}} & (7)\end{matrix}$wherein X_(Lcoil) is the inductive reactance of the coil assembly 115.

Equation (7) demonstrates that in order to increase the quality factorQ, X_(Lcoil) may be increased and R_(equiv) decreased. However, resonantcavities are configured to operate at a given resonant frequency. As aresult, changing coil inductance will change the resonant frequency.

One approach for decreasing R_(equiv) according to embodiments of thepresent disclosure is demonstrated by the the resonant RF cavity of FIG.3 . As shown, the resonator 100 may further include an exciter coil 124within the internal cavity 104. The exciter coil 124 may be positionedin close proximity to the coil assembly 115 to transfer energy (e.g., RFenergy) from an energy source 128. In some embodiments, the energysource 128 includes an RF generator 130, wherein impedance (Z₀) 132 isthe impedance of the RF generator 130, which may be equal to 50 ohms.

In one example, in order to find the analytical expression of Q, theinternal cavity 104 may be modeled as a lumped element circuit 170,shown in FIG. 4. In this example, R_(coil) is the resistance of the coilassembly 115, R_(junc) is the resistance of a junction 147 between thecoil assembly 115 and the housing 102, R_(can) is the resistance of thehousing 102, and R_(gap) is the resistance of the second gap 155. Basedon circuitry analysis, it can be shown that equivalent resistance can bewritten asR _(equiv)≈2(R _(coil) +R _(junc) +R _(can))+λR _(gap)  (8)

where X is a number between 0 and 1.

The resistance of the RF resonant cavity can be decreased by increasingthe size of the housing 102 (smaller induced image current), but thiswill increase the can capacity and alter the resonant frequency. Theresistance of the junction to ground and the gap resistance aredifficult to modify. Therefore, an effective way to increase the qualityfactor is to decrease the coil resistance, which is given by thefollowing equation:

$\begin{matrix}{R_{coil} = {\rho\frac{\ell}{A}}} & (9)\end{matrix}$where ρ is the resistivity of the coil material, l the length of thecoil tubing, and A the cross-sectional area through which the electriccurrent is flowing through the coil assembly 115. Thus, the total coillength will not be affected, but the current will see a widercross-section and therefore the coil resistance will decrease.

Turning now to the end, cross-sectional view of FIG. 5 , the first andsecond coils 105, 106 according to embodiments of the present disclosurewill be described in greater detail. As shown, the first and secondcoils 105, 106 may have an asymmetrical profile, wherein a first, innerside 134 has a flattened surface 185 and a second, outer side 166 has acurved surface 168. In this embodiment, an internal channel 161 isdefined by an internal surface 162 of the first and second coils 105,106. Although shown as having a circular profile, it'll be appreciatedthat the internal channel 161 may take on any variety of shapes.

As depicted, the first and second coils 105, 106 may be flattened orreduced from a circular profile 164 (as shown by dashed line) by adistance ‘d’ along a radial direction. Unlike direct current, RF currentdoes not flow through the whole radial cross-section of the first andsecond coils 105, 106 but through a small skin layer 148 at the innerside 134. The thickness of the skin layer 148 may be defined by thefollowing equation:

$\delta = \sqrt{\frac{2\rho}{2\pi\; f\;\mu_{0}\mu_{r}}}$wherein f is the RF frequency and wherein μ₀=4π×10⁻⁷ H/m and μ_(r) arethe magnetic permeability of the vacuum and the relative permeability ofthe material of the first and second coils 105, 106. If copper materialis used for the first and second coils 105, 106, then thethickness/depth of the skin layer 148 at 22 MHz is approximately 15 μm.

Furthermore, the cross-sectional area through which current flows(hashed area) may be defined by the following equation:

$A_{2} \simeq {2\delta\sqrt{2{dR}}}$

Compared to the circular profile 164, a flattening of the first coil 105and the second coil 106, for example, by a distance of approximately 1mm, may result in a 16-fold increase in the cross-sectional area of theskin layer 148. This will cause a decrease in the equivalent resistanceof the first and second coils 105, 106. Meanwhile, providing the outerside 166 with a curved surface or curved profile reduces an amount ofelectric stress, e.g., present with rectangular shaped electrodes due tothe small radii of curvature, which increases multipacting and the riskof dielectric breakdown.

Turning now to the side, cross-sectional view of FIG. 6 , a simplifieddepiction of the coil assembly 115 including the first and second coils105, 106 according to embodiments of the present disclosure will bedescribed in greater detail. As shown, the first coil 105 includes thefirst plurality of loops 123A-123C and the second coil 106 includes thesecond plurality of loops 127A-127C. Although only three (3) loops areshown for each of the first coil 105 and the second coils 106 for easeof explanation, it'll be appreciated that a lesser or greater number ofloops is possible.

The first plurality of loops 123A-123C and the second plurality of loops127A-127C may be winded in a same direction about the central axis 120.As shown, the first plurality of loops 123A-123C and the secondplurality of loops 127A-127C may generally have a same or similarradius. The first plurality of loops 123A-123C may include a first axialend 126 opposite a second axial end 129, and the second plurality ofloops 127A-C may include a third axial end 137 opposite a fourth axialend 139. The first axial end 126 and the third axial end 137 correspondto opposite ends of the overall coil assembly 115, while the secondaxial end 129 and fourth axial end 139 are positioned directly adjacentone another along an interior 141 defined by first and second coils 105,106. In some embodiments, each of the first plurality of loops 123A-123Cand the second plurality of loops 127A-127C may be spaced equidistantapart from one another, e.g., along the central axis 120.

As shown, each of the first plurality of loops 123A-123C has acorresponding first flattened surface 171A-171C, while each of thesecond plurality of loops 127A-127C has a corresponding second flattenedsurface 173A-173C. Each of the first flattened surfaces 171A-171C andsecond flattened surfaces 173A-173C define corresponding planes. Forexample, first flattened surface 171A may define a first plane 150disposed at a non-zero angle ϕ with respect to the central axis 120.First flattened surface 171B may define a second plane 151 disposed atnon-zero angle β with respect to the central axis 120. In someembodiments, ϕ>β. Meanwhile, first flattened surface 171C may define athird plane 152, which is generally parallel to the central axis 120.

Similarly, second flattened surface 173A may define a fourth plane 174disposed at a non-zero angle ρ with respect to the central axis 120. Insome embodiments, non-zero angle ϕ of the first plane 150 may be thesame as the non-zero angle ρ of the fourth plane 174. Second flattenedsurface 173B may define a fifth plane 175 disposed at non-zero angle αwith respect to the central axis 120. In some embodiments, non-zeroangle β of the second plane 151 may be the same as the non-zero angle αof the fifth plane 175. In some embodiments, ρ>α. Meanwhile, secondflattened surface 173C may define a sixth plane 176, which is generallyparallel to the central axis 120 and to the third plane 152. In someembodiments, the first and second plurality of loops 123A-123C,127A-127C may have a generally D-shaped profile.

As demonstrated, the first flattened surface 171A and the secondflattened surface 173C flare outwardly at the first axial end 126 andthe third axial end 137, respectively. As a result, the area of the coilsurface that is carrying the current is greatly increased, significantlyreducing the resistance of the RLC circuit and improving the Q.

Turning now to the end, cross-sectional view of FIG. 7 , an alternativecoil 205 according to embodiments of the present disclosure will bedescribed. As shown, the coil 205 may have an asymmetrical profile,wherein a first, inner side 234 has a flattened surface 235 and asecond, outer side 236 has a curved surface 238. In this embodiment, aninternal channel 240 is defined by an internal surface 242. Althoughshown as having a circular profile, it'll be appreciated that theinternal channel 240 may take on any variety of shapes.

As shown, the coil 205 may include a planar component 210 extendingaxially along a length thereof. The planar component 210 may be providedto further increase an area of a skin layer 248 available to carry thecurrent and thus further reduce the equivalent resistance of the coil205. Although non-limiting, the planar component 210 may include a firstmain surface 260 opposite a second main surface 262. The skin layer 248may extend along the first main surface 260.

In view of the foregoing, at least the following advantages are achievedby the embodiments disclosed herein. A first advantage includes drivingup the quality factor by decreasing the resistance of the coil assembly.A second advantage includes increasing the available accelerationvoltage as a result of the higher quality factor.

The foregoing discussion has been presented for purposes of illustrationand description and is not intended to limit the disclosure to the formor forms disclosed herein. For example, various features of thedisclosure may be grouped together in one or more aspects, embodiments,or configurations for the purpose of streamlining the disclosure.However, it should be understood that various features of the certainaspects, embodiments, or configurations of the disclosure may becombined in alternate aspects, embodiments, or configurations.

As used herein, an element or step recited in the singular and proceededwith the word “a” or “an” should be understood as not excluding pluralelements or steps, unless such exclusion is explicitly recited.Furthermore, references to “one embodiment” of the present disclosureare not intended to be interpreted as excluding the existence ofadditional embodiments that also incorporate the recited features.

The use of “including,” “comprising,” or “having” and variations thereofherein is meant to encompass the items listed thereafter and equivalentsthereof as well as additional items. Accordingly, the terms “including,”“comprising,” or “having” and variations thereof are open-endedexpressions and can be used interchangeably herein.

The phrases “at least one”, “one or more”, and “and/or”, as used herein,are open-ended expressions that are both conjunctive and disjunctive inoperation. For example, each of the expressions “at least one of A, Band C”, “at least one of A, B, or C”, “one or more of A, B, and C”, “oneor more of A, B, or C” and “A, B, and/or C” means A alone, B alone, Calone, A and B together, A and C together, B and C together, or A, B andC together.

All directional references (e.g., proximal, distal, upper, lower,upward, downward, left, right, lateral, longitudinal, front, back, top,bottom, above, below, vertical, horizontal, radial, axial, clockwise,and counterclockwise) are only used for identification purposes to aidthe reader's understanding of the present disclosure, and do not createlimitations, particularly as to the position, orientation, or use ofthis disclosure. Connection references (e.g., attached, coupled,connected, and joined) are to be construed broadly and may includeintermediate members between a collection of elements and relativemovement between elements unless otherwise indicated. As such,connection references do not necessarily infer that two elements aredirectly connected and in fixed relation to each other. Furthermore,identification references (e.g., primary, secondary, first, second,third, fourth, etc.) are not intended to connote importance or priority,but are used to distinguish one feature from another.

Furthermore, the terms “substantial” or “substantially,” as well as theterms “approximate” or “approximately,” can be used interchangeably insome embodiments, and can be described using any relative measuresacceptable by one of ordinary skill in the art. For example, these termscan serve as a comparison to a reference parameter, to indicate adeviation capable of providing the intended function. Althoughnon-limiting, the deviation from the reference parameter can be, forexample, in an amount of less than 1%, less than 3%, less than 5%, lessthan 10%, less than 15%, less than 20%, and so on.

Still furthermore, although the illustrative methods described above asa series of acts or events, the present disclosure is not limited by theillustrated ordering of such acts or events unless specifically stated.For example, some acts may occur in different orders and/or concurrentlywith other acts or events apart from those illustrated and/or describedherein, in accordance with the disclosure. For example, the hereindescribed process sequence of performing the implant process, formationof stress film, annealing, and removal of the stress film can berepeated a number of times to create multiple stress memorization layersor areas.

In addition, not all illustrated acts or events may be required toimplement a methodology in accordance with the present disclosure.Furthermore, the methods may be implemented in association with theformation and/or processing of structures illustrated and describedherein as well as in association with other structures not illustrated.

The present disclosure is not to be limited in scope by the specificembodiments described herein. Indeed, other various embodiments of andmodifications to the present disclosure, in addition to those describedherein, will be apparent to those of ordinary skill in the art from theforegoing description and accompanying drawings. Thus, such otherembodiments and modifications are intended to fall within the scope ofthe present disclosure. Furthermore, the present disclosure has beendescribed herein in the context of a particular implementation in aparticular environment for a particular purpose. Those of ordinary skillin the art will recognize the usefulness is not limited thereto and thepresent disclosure may be beneficially implemented in any number ofenvironments for any number of purposes. Thus, the claims set forthbelow are to be construed in view of the full breadth and spirit of thepresent disclosure as described herein.

What is claimed is:
 1. A resonator, comprising: a conductive hollowtube, comprising: a first end coupled to a first electrode, the firstelectrode operable to accelerate ions; a central section connected tothe first end, wherein the central section extends about a central axis,wherein an inner side of the central section has a flattened surface,and wherein an outer side of the central section has a curved surface;and a second end connected to the central section.
 2. The resonator ofclaim 1, wherein the central section extends helically about the centralaxis.
 3. The resonator of claim 1, wherein the central sectioncomprises: a first axial end and a second axial end; and a plurality ofloops extending between the first and second axial ends, wherein a firstloop of the plurality of loops includes a first flattened surfacedefining a first plane, wherein a second loop of the plurality of loopsincludes a second flattened surface defined a second plane, and whereina first angle, with respect to the central axis, of the first plane isdifferent than a second angle of the second plane.
 4. The resonator ofclaim 3, wherein the first angle is greater than the second angle. 5.The resonator of claim 3, wherein the first loop is positioned at thefirst axial end, and wherein the second loop is positioned at the secondaxial end.
 6. The resonator of claim 1, further comprising a secondconductive hollow tube coupled to a second electrode, wherein an ionbeam is operable to pass through the first and second electrodes, andwherein the second conductive hollow tube comprises plurality of loopsextending helically about the central axis.
 7. The resonator of claim 6,wherein the conductive hollow tube is disposed within a housing, andwherein the second end of the conductive hollow tube is coupled to thehousing.
 8. The resonator of claim 7, further comprising: an excitercoil within the housing; and an energy source connected with the excitercoil for providing radio frequency (RF) energy to the conductive hollowtube and to the second conductive hollow tube.
 9. A resonator,comprising: a coil disposed within a housing, the coil comprising: afirst end coupled to a first electrode, the first electrode operable toaccelerate ions; a central section connected to the first end, whereinthe central section extends helically about a central axis, wherein aninner side of the central section has a flattened surface, and whereinan outer side of the central section has a curved surface; and a secondend connected to the central section, wherein an internal channelextending between the first and second ends is operable to transport afluid.
 10. The resonator of claim 9, wherein the central sectioncomprises: a first axial end and a second axial end; and a plurality ofloops extending between the first and second axial ends, wherein theinner side of a first loop of the plurality of loops defines a firstplane, wherein the inner side of a second loop of the plurality of loopsdefines a second plane, and wherein a first angle of the first plane,with respect to the central axis, is different than a second angle ofthe second plane, with respect to the central axis.
 11. The resonator ofclaim 10, wherein the first loop is positioned at the first axial end,wherein the second loop is positioned at the second axial end, andwherein the first angle is greater than the second angle.
 12. Theresonator of claim 9, further comprising a second coil within thehousing, wherein the second coil is coupled to a second electrode, andwherein an ion beam is operable to pass through the first and secondelectrodes.
 13. The resonator of claim 12, wherein the second end of thecoil is coupled to the housing.
 14. A resonator of an ion implanter, theresonator comprising: a housing defining an internal cavity; a hollowcoil partially disposed within the internal cavity, the hollow coilcomprising: a first end coupled to a first electrode, the firstelectrode operable to accelerate ions; a central section connected tothe first end, wherein the central section extends helically about acentral axis, wherein an inner side of the central section has aflattened surface, and wherein an outer side of the central section hasa curved profile; and a second end connected to the central section andto the housing.
 15. The resonator of claim 14, wherein the centralsection comprises: a first axial end and a second axial end; and aplurality of loops extending between the first and second axial ends,wherein the inner side of a first loop of the plurality of loops definesa first plane, wherein the inner side of a second loop of the pluralityof loops defines a second plane, and wherein a first angle of the firstplane, relative to the central axis, is different than a second angle ofthe second plane, relative to the central axis.
 16. The resonator ofclaim 15, wherein the first loop is positioned at the first axial end,wherein the second loop is positioned at the second axial end, andwherein the first angle is greater than the second angle.
 17. Theresonator of claim 14, further comprising a second coil partiallydisposed within the internal cavity, wherein the second coil is coupledto a second electrode and to the housing, and wherein an ion beam isoperable to pass through the first and second electrodes.
 18. Theresonator of claim 14, wherein the flattened surface faces the centralaxis.
 19. The resonator of claim 14, wherein the hollow coil has aD-shaped profile.